The invention relates to electrical circuit boards, and more specifically, to a capture device for use with circuit boards having variable thickness to prevent the space between the circuit boards from increasing.
Computers and other devices that include digital logic components typically employ one or more circuit boards populated with any of small, medium, or large scale logic components, typically in the form of integrated circuits, as well as occasional discrete components. Electrical signals and power are transferred between boards through electrical connectors, typically complimentary mating pin connectors. It is common for a primary circuit board (a mother board) to provide power and signals to a secondary or supplemental circuit board (a daughter board), such as a memory card. In such instances, the electrical connection between the mother board and daughter, board must be maintained in order for the daughter board to function properly. The preferred spacing between the circuit boards, therefore, is defined by the spacing necessary for optimal mechanical and electrical contact between the complimentary electrical connectors on each respective board. Accordingly, the space between the interior or facing surfaces of two connected circuit boards is fairly well defined by the combined profile of the connectors. If the only feature mechanically coupling the mother board to the daughter board is an electrical pin connector, it is possible for the daughter board to work loose or xe2x80x9cback-outxe2x80x9d from the mother board, particularly since the daughter board may be of smaller size than the mother board. This problem also arises when two similar size boards are mechanically and electrically coupled through only a pin connector. One prior art solution to this problem has been to mechanically secure the boards together using a spacing post, sometimes called a standoff, and screws. However, such devices are sometimes difficult to install and uninstall, particularly when boards are being swapped in existing installed system where space may be very limited. Accordingly, a need exists for a device that mechanically secures a plurality of circuit boards, including mother boards and daughter boards, in a fixed relation to prevent the space between the boards from increasing, i.e. back-out.
In addition, although the space between the interior or facing surfaces of two connected circuit boards is typically defined by the combined profile of the connectors on the circuit boards, the height between the exterior surfaces of the joined boards may vary depending on the thickness of the boards. Current fabrication techniques allow circuit boards to have multiple layers of signal paths therein, increasing the thickness of the boards. As such, the required spacing between the respective non-connecting surfaces of two circuit boards may vary depending on the thickness of the circuit boards to be joined. Accordingly, a need exists for a device that can mechanically clamp two circuit boards together and that can accommodate a variety of spacing distances between the exterior, non-facing surfaces of the boards.
Further, circuit boards are often mechanically and electrically coupled during both assembly of a computer system as well as during upgrading and maintenance of a computer system once assembled. For example, daughter boards that add additional functionality and/or memory to a mother board are often inserted by a field engineer. Typically, the existing space into which the board must be inserted has limited access making it very difficult to use mechanical fasteners, i.e., screws and standoffs to secure circuit boards together. In addition, mechanical coupling of such boards is often done without the benefit of the technician being able to see the boards and components clearly. Accordingly, a need exists for a device that can be used to capture and mechanically join circuit boards with limited access thereto. A further need exists for a device that can be clamped and unclamped from circuit boards using primarily the tactile sense, without the benefit of sight.
A capture device for use with circuit boards having variable thickness includes a unitary body including a flexible arm, a clip cavity and multiple living hinges that enable the capture device to be pivotally locked between multiple circuit boards whose intermediate spacing height varies. The capture device can be engaged and disengaged in poor visibility and limited access areas with densely packed circuit boards. The capture device may be made of a semi-rigid material that provides enough flexibility for the living hinges, yet is rigid enough to maintain the boards at respective distances. In alternative embodiments, more than two circuit boards may be secured using alternative configurations of the capture device with either multiple arms or multiple clip cavities.
According to a first aspect of the present invention, an apparatus for removably securing multiple circuit boards comprises (a) a main body capable of receiving a first circuit board; (b) a first arm pivotally joined to the main body; and (c) an engaging mechanism formed at an end of the first arm for engaging and removably securing another circuit board in spaced relation to the first circuit board. In one embodiment, the first arm and the main body are joined with a first living hinge. In another embodiment, an elbow is integrally formed in the first arm and joined with a living hinge which forms an angle of less than ninety degrees between the elbow and the first arm. In other embodiments, the capture device further comprises a second arm pivotally joined to the main body and a second engaging mechanism formed at an end of the second arm for engaging and removably securing another circuit board in spaced relation to the first circuit board.
According to a second aspect of the present invention, an apparatus for removably securing multiple circuit boards comprises (a) a main body capable of receiving a first circuit board; (b) a first arm; (c) means for pivotally attaching the first arm to the main body; and (d) engaging means formed at the end of the first arm for engaging and removably securing another circuit board in spaced relation to the first circuit board. In one embodiment, the means pivotally attaching the first arm to the main body comprises a first living hinge. In another embodiment, an elbow is integrally formed in the first arm and joined with a living hinge which forms an angle of less than ninety degrees between the elbow and the first arm. In other embodiments, the capture device further comprises a second arm pivotally joined to the main body and a second engaging mechanism formed at an end of the second arm for engaging and removably securing another circuit board in spaced relation to the first circuit board.
According to a third aspect of the present invention, a method for removably securing multiple circuit boards comprising: (a) providing a capture device comprising: i) a main body capable of removably receiving a circuit board; ii) a first arm pivotally joined to the main body, and iii) an engaging mechanism formed at an end of the arm for engaging and removably securing another circuit board in spaced relation to the first circuit board; (b) engaging a first circuit board with the capture device; and (c) pivoting one of the main body and first arm to engage a second circuit board with the capture device. In another embodiment the method further comprises, applying force on the circuit boards with the capture device to maintain the circuit board in a spaced relation.